Did Rene Descartes correctly describe the essence of the glymphatic system 382 years before if was formally observed[1]?

The glymphatic system is a network of brain cells and blood vessels that functions to maintain brain health by clearing waste products and regulating fluid balance. It functions similarly to the lymphatic system in the rest of the body but is specifically adapted to the brain's unique needs. This system functions to remove waste generated by neuronal activity including amyloid beta and tau proteins which are implicated in dementia. Cerebrospinal fluid flows along the interstitial spaces flushing out waste products which are then absorbed into the vascular circulation. Solute regulation is a critical aspect of maintaining extracellular fluid volume within the brain directly affecting function and pressure. Think of a critically ill trauma patient who is placed on hypertonic saline to reduce intracranial pressures. From a cell-based perspective, astrocytes interact with the glymphatic system via a specialized appendage that guides CSF into the interstitial spaces of the brain facilitating the removal of waste products.
Importantly, the glymphatic system is most active during sleep, especially REM sleep. It has been observed that during sleep, the brain cells reduce in size creating additional space for CSF to flow and remove waste. A lack of sleep impairs this system which can contribute to worsening neurodegenerative processes.
Rene Descartes (1596 –1650) wrote translated from the original French, “Moreover, during sleep the substance of the brain, being in repose, has leisure to be nourished and repaired, being moistened by the blood contained in the little veins or arteries that are apparent on its external surface. Whence, after some time, the pores having narrowed, the spirits need to be less strong to keep the brain substance quite tense (just as the wind needs to be less strong to inflate a ship’s sails when damp than when dry). And yet these spirits [in the brain ventricles] are stronger [during sleep than at other times], inasmuch as the blood producing them is purified while passing and repassing several times through the heart…for during waking, the substance of the brain is dried out and its pores are gradually enlarged by the continual action of the spirits.”

[1] Iliff JJ, Wang M, Liao Y, et al. A paravascular pathway facilitates CSF flow through the brain parenchyma and the clearance of interstitial solutes, including amyloid β. Sci Transl Med. 2012;4:147ra111. doi: 10.1126/scitranslmed.3003748.
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